S40 2.0D No boost pressure - boost hose sucking flat

[Sonnypepper]

Evening all,

I have a 2008 S40 2.0D which I brought needing a clutch, the car had a code P0299 when I brought it which is turbo charger control valve underboost pending code. This didn’t affect driving at all as prior to changing the clutch whatever little clutch was left was able to drive the car hard; accelerating well in all gears etc.

To replace the clutch, this requires the removal of the hard pipe from the hot side of the intercooler to the turbo. This is at the bottom of the engine on the passenger side. I’m not sure if this was occurring pre clutch change however the rubber pipe that connects the hard pipe to the intercooler sucks completely flat.

Since putting it back together I have still got the P0299 code however the car is not boosting at all and will not rev over 2000 RPM either stationary or moving. I have checked the boost control valve with the VAC and OUT ports and both hold vacuum, and when plumbed in the turbo actuator rod can be seen moving when revving up.

I have done some research and can see previous posts with peoples hoses intake side of the intercooler sucking flat however not much on the hot side pre intercooler sucking flat. The prognosis of the former is usually a blown turbo or blocked intercooler as the engine is trying to suck air past a blockage and when unable to sucks it from else where.

Im trying to visualise how this works but I’m struggling. To me the intercooler is ruled out as the hose collapsing is before the intercooler, the only other things up stream of that is the turbo and the air box?

Doing some reading of the turbo replacement procedure on these models, it seems like a pain in the arse, the removal of engine mounts etc and moving the engine forward so I haven’t attempted this to check for end float yet. Is this the next move?

Any advice would be much appreciated.

Sonny

[IainG]

Hi
Have you checked your air filter?
Just give it a quick test without the air filter ??

[Simmy]

check for any obstructions which may have been left behind from a prievious smoke test. iv. seen this before and its hard to diagnose .

[moorgate]

I had this on my V70 D5. The unboosted side elbow hose, with the junction for part of the EGR system on it, was completely polluted by oil leaking from (we thought) the turbo, though it might have been the EGR too which was like xmas pud inside the piping!

A new hose and a weekend wrangling dessert spoons and flattened wire coat-hangers around the EGR system, scooping out gack, revolutionised the car.

[Sonnypepper]

Originally Posted by moorgate

I had this on my V70 D5. The unboosted side elbow hose, with the junction for part of the EGR system on it, was completely polluted by oil leaking from (we thought) the turbo, though it might have been the EGR too which was like xmas pud inside the piping!

A new hose and a weekend wrangling dessert spoons and flattened wire coat-hangers around the EGR system, scooping out gack, revolutionised the car.

I’ve just removed the EGR pipe and ran the car without the air box and now the hot side boost pipe isn’t sucking flat and the car revs up to red line. I have found if I block the intake side of the EGR pipe the hot side intercooler pipe begins to suck flat. I can see the intake manifold is full of crap as is the EGR valve. (Please see below pics) does this mean I’m not in the market for a new turbo and the EGR system is to blame?





Sonny

[Simmy]

no pic showing sonny remove all egr pipe work and cooler also clean out the throttle body and any sensors in the pipe work and throttle body don't over tighten when replacing the tb as this can cause a different fault. when you get it running do a scan to determine if the egr is working if its not operating this will contribute to the blocking of your pipe work.`` be warned its a very dirty job

[Sonnypepper]

Originally Posted by Simmy

no pic showing sonny remove all egr pipe work and cooler also clean out the throttle body and any sensors in the pipe work and throttle body don't over tighten when replacing the tb as this can cause a different fault. when you get it running do a scan to determine if the egr is working if its not operating this will contribute to the blocking of your pipe work.`` be warned its a very dirty job

https://freeimage.host/i/JfSSlIa
https://freeimage.host/i/JfSSJs4So
https://freeimage.host/i/JfSUsSI
https://freeimage.host/i/JfSSJs4

Sorry Simmy, I’m not used to this forum. I hope this works. The photo with the key in it is the intake side of the EGR pipe which is definitely dirty but not the worst I’ve ever seen. The valve side of the pipe is black but isn’t caked. The intake is definitely full of cack. I’m not opposed to a dirty job, the clutch was a pretty filthy job! I’ll get cleaning this weekend.

I’m wondering if what I’ve described would lead anyone to think it’s more of an EGR problem? The car wouldn’t rev up to more than 1.8 - 2.2 k and would get an underboost code with the hot side intercooler pipe sucking flat. I had all but condemned the turbo as I couldn’t see where else the restriction could be coming from?

I’m also slightly confused as I thought the removal of the EGR pipe would cause an underboost issue not solve it?

Sonny